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This paper aimed at the characters, diffusivity and application of multi-component refrigerants during different immersion chilling and freezing associated with static processing and dynamic processing.The higher freezing point and corrosivity of sodium calcium water solution ,strong volatility of ethanol solution and the high impregnation from solutes restrict the development of immersion chilling and freezing technique. The diffusivity from solutes to gelatin models was investigated; the selected quaternary refrigerant was used to freeze the grass carp and compared with air-blast freezing. The results are as following:(1) The selected quaternary refrigerants composed of sodium chloride, ethanol and propylene glycol, have low freezing points,high heat transfer and low diffusivity. The research showed that the solutions with the best contents were ethanol 20%,propylene glycol 14%,sodium chloride 4% at -20℃,ethanol 20%,propylene glycol 21%,sodium chloride 4% at -30℃,ethanol 20%,propylene glycol 30%,sodium chloride 4% at -40℃.Compared to current common salt solution and ethanol solution refrigerants, they can be well used in immersion chilling and freezing, and have good thermal transfer and mass transfer.(2) In order to reveal the diffusivity of the solutes from the solution of quaternary refrigerant liquid to food in static freezing process, the freezing process in different condition was investigated,and the inflences of such immersion chilling and freezing variables as temperature, freezing time and total concentration on the absorption of NaCl, ethanol, propylene glycol and the total absorption were analyzed on a gelation cylinder model.Results indicated that the absorption of NaCl,ethanol, propylene glycol as well as total absorption remarkably improves; the diffusivity of the solutes decreases at low initial temperature; high solution concentration may result in higher total absorption; in the freezing conditions of -40~-20℃in this work, the total absorption is found to be only 2.70~6.23mg/g after 25min.(3) In order to reveal the diffusivity of the solutes from the solution of quaternary refrigerant liquid to food in dynamic freezing process, freezing time and flow rate were investigated; Compared with other solutions, ethanol 20%,propylene glycol 21%,sodium chloride 4% whose freezing point is -40℃has smaller viscosity and less solutes absorption, which is fit for application of freezing grass carp. Heat transfer process was improved greatly as the flow rate increasing, the core temperature of gelatin cylinder could fall to -10℃in 15min ,however 25min static condition. Solutes absorption fluctuate but all the components have the same trend as the flow rate increasing. In this work the total absorption is found to be only 1.97~2.83mg/g.(4) Based on the discipline of multi-component refrigerant diffusivity, the selected solution was used to freeze grass carp. Results indicated that the frozen rate of ICF exhibited 1.5-fold faster than that of air-blast freezing. The uptake amounts of sodium chloride, ethanol, and propylene glycol in grass carp were 0.14%, 0.17%, 0.63% and 0.94%, respectively. Compared with traditional air-blast freezing, ICF-treated samples had higher salt-soluble protein, less lipid oxidation, reduced drip loss and low moisture loss. Therefore, ICF exhibited more beneficial for maintaining texture properties and provided a better quality for grass carp during frozen storage(5)The selected ethanol 20%,propylene glycol 21%,sodium chloride 4% at -27℃is suitable for using in designed divice; And it can be used to freeze materials such as rice dumpling and fish ball whose diameter are not more than 25mm or fish fillets.
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